The present invention relates a system for determining a fuel property (heavy/light property) of fuel used in an internal combustion engine.
Japanese Published Patent Application No. 9-151777 discloses a method of determining a fuel property (heavy/light property) of fuel in use by detecting a revolution speed difference per each predetermined cycle such as a ½ engine revolution after a cranking speed reaches a predetermined cranking speed such as a cranking speed of 300 rpm, and by determining whether or not the number of the elapsed cycles is greater than or equal to a predetermined value when the sum of the revolution speed differences becomes greater than or equal to a predetermined value.